1. Field of the Invention
This invention relates to exhaust systems for nuclear reactor installations, and more particularly to such exhaust systems used for ventilation of reactor containment refueling canals for the purpose of capturing, for processing, gases and vapors which may be emitted from the surface of the refueling canal, and to prevent the release of radioactive gases to the containment during refueling as a result of a burst of gas which might result in the unlikely event of a dropped fuel assembly or leaky fuel.
2. Description of the Prior Art
Nuclear reactors, particularly nuclear reactors designed and utilized as electric power generating plants, are generally enclosed within a containment. Such reactor installations are also provided with fuel handling and storage facilities, which are often located in separate, adjacent buildings. Reactors, such as pressurized water reactors, generally utilize as a part of the installation a canal filled with water, which is located at one end over the reactor vessel, through which nuclear fuel elements are transported under water to and from the reactor and the separate fuel handling building. During refueling, used fuel elements are removed from the reactor and new fuel elements are inserted into the reactor core. The provision of the canal within and between the containment and fuel handling building allows the fuel elements to be handled under water for cooling and shielding of radioactivity from the fuel elements to the surrounding atmosphere and the operators. However, in the unlikely event a fuel element is dropped within the canal and its integrity is breached to the extent to permit the release of radioactive gases normally contained within the fuel element, or for other reasons a release of radioactive gases should occur, it is desirable to contain such radioactive gases as may be emitted from the surface of the refueling canal in order to prevent possible radioactive contamination within the containment or fuel handling building. Therefore, a system is desired to completely purge the surface above the refueling canal in the containment and fuel handling building to prevent such release of radioactive gases. The normal exhaust arrangements for reactor purge systems are not designed to handle such a contingency.
It is an object of the instant invention to provide an exhaust system to capture radioactive gases which may be emitted from the surface of the refueling canal during refueling.
It is a further object of this invention to provide such a system which captures the gases for processing before they can spread within occupancy areas.
It is a still further object of the invention to provide a system for the prevention of moisture buildup within the atmosphere due to evaporation of water from the refueling canal.